VME Bus Questions

[Mike Moore]

I have some questions about the operation of the VME bus on the Sun 3/1xx
machines.  

1. When a device on the bus gets a SYSRESET, how much time does it have to
set its base address to avoid conflict other devices?  Can a slave board
hold its SYSRESET low (after the specified time, as in VME spec,
permission 5.4) in order to complare its own initialization, without
screwing up the boot somehow?

2. In the device driver, does the xxprobe() routine's return size include
space for the DMA channels?  Once the system is up, can the addresses be
reset?

3. What special procedures are needed during the autoconfigure process to
assure the proper return of the routine? What could cause this routine to
bus error on return?

4. If a device on the bus has dual-ported RAM (i.e., RAM that appears in
both the VME bus space and the board's CPU bus space concurrently), how
easy is it to map this area into the SUN MMU's virtual address space? Is
this kosher?

Thanks in advance for the assistance,

Mike Moore
CIM Project Manager - Sun Microsystems
mrmoore at sun.com
408-276-5008